fix: make Python algorithms consistently return a VectorFst #1276

Job	Run time
Check python formatting	7s
Check rust formatting	15s
Fetch or Build OpenFST (ubuntu-latest)	6s
Fetch or Build OpenFST (macos-13)	17s
rustfst-python-bench	2m 28s
rust-clippy	22s
rust-doc	15s
python-doc	35s
rustfst-python (ubuntu-latest)	48s
rust-tests (1.74.0, ubuntu-latest, --all --benches --examples --bins --tests)	2m 5s
rustfst-python (macos-13)	1m 4s
rust-tests (1.74.0, ubuntu-latest, --manifest-path rustfst/Cargo.toml --features "state-label-u32")	2m 8s
rust-tests (1.74.0, macos-13, --all --benches --examples --bins --tests)	2m 24s
rust-tests (1.74.0, macos-13, --manifest-path rustfst/Cargo.toml --features "state-label-u32")	2m 8s
rust-tests (stable, ubuntu-latest, --all --benches --examples --bins --tests)	2m 6s
rust-tests (stable, ubuntu-latest, --manifest-path rustfst/Cargo.toml --features "state-label-u32")	2m 22s
rust-tests (stable, macos-13, --all --benches --examples --bins --tests)	2m 16s
rust-tests (stable, macos-13, --manifest-path rustfst/Cargo.toml --features "state-label-u32")	2m 18s
Publish Python Wheels to PyPI	0s
Publish Rust Crate to Crates.io	0s
Publish rustfst-python's doc	0s
	24m 4s

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